Novel hexafluorohexenes

ABSTRACT

Cis and trans-1-trifluoromethyl-1,2,2-trifluoro-4methylcyclobutane and mixtures thereof are provided. These compositions are liquids having high dielectric constant and low freezing points, useful as working fluids for hydraulic systems and as inert solvents. Also provided are linear dimers, 4,4,5,6,6,6-hexafluorohexene-1 and 4,4,5,6,6,6-hexafluorohexene2, useful as comonomers in ethylene and propylene polymerization.

United States Patent LaLande, Jr. et al.

NOVEL HEXAFLUOROHEXENES Inventors: William Alfred LaLande, Jr.,

Philadelphia; Murray Hauplschein, Glenside; Robert Bonner Hager,Collegeville all of Pa.

Assignee: Pennwalt Corporation, Philadelphia Filed: Nov. 14. 1973 Appl.No: 415,580

Related US. Application Data Division of Ser No. M6503. May 24 |J7labandoned.

US. Cl. 260/6531 R; 260/6533; 260/648 F;

252/78; 252/66; 252/364 Int. Cl C070: 17/26; C07c 2l/I8 Field of Search260/653.l R, 653.3

Oct. 7, 1975 [56] References Cited UNITED STATES PATENTS 3.406.2[010/1968 Schmerling 260/651] R 1789988 l/l974 LaLande, Jr.; et a],260/653} Primary ExaminerDaniel Dv Horwitz 5 7 ABSTRACT 7 Claims, N0Drawings NOVEL HEXAFLUOROHEXENES This is division, of application Ser.No. 146,503. filed May 24. 1971. now US. Pat. No. 3,789,088.

The compositions of this invention are a mixture of cis-andtransl-trifluoromethyll .2.2-trifluoro-4- methylcyclobutane. referred toas the mixed cyclic dimer or l:l cycloadducts of hexafluoropropene andpropylene. the individual cyclic dimers, and the l:] linear adducts (orlinear dimers) 4.4.5.6,6-hcxafluorohexene-l and4,4,5.6.6.6-hexafluorohexene-2. These new compounds are produced by thethermally-promoted reaction of hexafluoropropene and propylene.

The cyclic compositions of this invention, trifluoromethyll ,2.2-trifluoro-4-methylcyclobutane,

are produced a mixture of the cis-isomer H cH.

wherein the ratio of cisztrans isomer may be in the range of about 5:95to 95:5. The individual cis and trans isomers can be isolated by gaschromatography separation techniques well known to those skilled in theart.

The hexafluoropropene-propene cyclic adducts embodied herein havecertain unexpected physical characteristics which distinguish them fromsuperficially structurally similar products. giving the new products awider range of utility. including new and diverse uses. Their valuableand distinguishing properties are noted when compared to the cyclicdimer of hexafluoropropene (perfluorodimethylcyclobutane) disclosed inUS. Pat. Nos. 2.957.032 and 3,3|6.3l2. and the cyclic dimer oftetrafluoroethylene and propylene l-methyl-2,2.3.3-tetrafluorocyclobutane) described by D. D. Coffman et al.. J.Am. Chem. Soc. 7]. pp. 490-96 I949 These differences are discussed inmore detail later in this specification.

The Compounds of this invention are prepared by bringing together themonomers hexafluoropropene and propylene. in mole ratios within therange of about [:1 to 1:20. at reaction temperatures of from about 200C.to about 800C.. preferably from 240 to 350C. Reaction pressures can varyfrom one to about 500 atmospheres. but prefereably will be in the rangeof 50 to 200 atmospheres. The reaction may be carried out eithercontinuously in a hot tube flow system or batchwise in a pressurevessel. Performing the reaction at lower temperatures, e.g., on theorder of about l20C., using di-tertiary-butyl peroxide as a catalyst.will favor the production of more of the linear, terminally unsaturatedadduct.

The invention is clarified by the following illustrative example.

To a 2-gallon stainless steel, stirred autoclave cooled in a DryIce/acetone bath are charged I755 g. (ll.7 moles) of perfluoropropeneand 905 g. (2 l .5 moles) of propylene. The autoclave is sealed andheated for 24 hours at 250C. with stirring. After cooling to roomtemperature. l63l g. of liquid and 906 g. of gas are recovered.Distillation of the liquid gives I361 g. (59% conversion) of the mixeddimer product of this invention. Mass spectral analysis shows themolecular weight to be 192, consistent with the stated structure. Fn.m.r. analysis gives the following data (expressed as ppm. fromtrifluoroacetic acid).

Isomer CF; C F CF trans +2.96 24.56. 28.36. 29.59. 33.4 I 16.5 cis l.7621.76. 25.58 39.09. 42.89 94.94

Isomer Bands trans 3.3lw. 3.34 w. 3.3) w. 345w. 675w. 68w. 7.25m.

7.5m. 7.6m. Kim. 8.31s. 8.42s. l().2m. ll).5w l3.5w. 15.6w microns cis131w. 334w. 139w, 145w. 675w. 68w. 7.25w.

7.5m. 7.6m. 8.Im.

8.35s. 8.5s. 8.8m. l0.45m 13.4w. 15.0w microns Anal. Calc'd. for C H FC. 37.5; H. 3.13; F. 594 Found: C. 37.2; H. 3.45; F. 60.1

The approximate ratio of the cis to trans isomer in this product is 1:1.The boiling point range of the dimer product is 84 to C., with thecis-isomer being the higher boiling component. Other important physicalproperties of the l-trifluoromethyl-l ,2,2-trifluoro-4-methylcyclobutane are:

1. Critical Temperature 250.3 i 5C.

2. Liquid density (g/ml) l.379l l.9l74XlO t 23.6C. s t S 150.3C. (1.3312at 25C.) Liquid density (g/ml) 4.8407 5.9O63Xl0 t 3.170X l0 t 5.9748XlO't l55C. s t s 239.8C.

3. Sat. vapor density (g/ml) 7.l963Xl0- t 5.6973Xl0 t l.5l5X10 t 0.28585l00.2 C. s t 239.8C.

The mean vapor and liquid density (du rm/2 O.6980969.6679Xl0" t 23.6 s ts 250.3C. The critical density is estimated to be 0.456 g/ml.

6. The index of refraction. n is l.3l50

7. Three purified samples gave liquid dielectric constants l7.8, 19.1.and l9.5 with dissipation factor less than l0". Average l8.8.

9. Glass point= l 30C.

where MR,, and n,, are. respectively. the molar refractivity and theindex of refraction for light at the wavelength of the sodium- D line(5890 angstroms) M is the molecular weight. and p is the density.Therefore. the molar refractivity is ('ompountl (iroup Bands Centerlppm) Coupling Consts (H CF; Double -2.2(1 J 1.7

quartet Jac 5.4

F ltll (Cl if) (g) (F f (F .-CH- (F AB system with 3 .75 Jgcm==169. chem.*(H=('H- i l'urther couplings shift of 1.7 ppm. (a) H CF doublesextuplet U483 .lbc=4l (H triplet. each Jde=l 7.5

component a Jct'=5.5 doubled doublet 2.36

=(H complex 4.71-5.88

(H(C) complex-approx. 4.37 jbe=47 a doubled scxtuplct CF double -l28 J=I(I quartet I 6 F l l (c) (l) (g) CF C--CF CH=CHC'H; CF AB system with28. 32.9 Jgcm==267 chem,

l further couplings 35, 39.9 shift of 5.2 ppm. (a) H CF double 133.3.l,,.=41

scxtuplct CH singlet 156 two singlets 5.08. 5.18 G l CH=CH- CH complex.approx. 4.51 l,,,.=4h

a douhlc sextuplet The average atomic refraction of thc fluorine atomgiven by Coffman, et al. (Loc. cit.) as 1.08 is in error and should be1.21. This is important only in comparing the experimental data. Usingthe (corrected) value of atomic refraction of Coffman et a1v (Loc. cit),the theoretical value based upon the additivity of the atomicrefractions (see S. Glasstone, Textbook of Physical Chemistry, 2nd Ed.,p. 53(1) is 28.4. This agreement between the molar refractivitycalculated from the experimental data and that calculated from theadditivity of atomic refractions is very good, and confirms theexperimental data.

The cyclic dimer of the invention is further distinguished from thetetrafluoroethylene-propylene adduct by its polarizability which can becompared from calculations based on the molar refraction. The totalpolarization which can be induced in a molecule is a sum of thepolarization which can be induced in the electron cloud of the molecule(PE) and that which can be induced through atomic polarizations (or atomdisplacements within the molecule) (P In general, the small P amounts toonly 5l0'7r of the value of P,; for radiation in the region of thesodium-D line. Light is an electromagnetic phenomenon and it istherefore not sur prising that there is a relation between the molarrefractivity and the total polarization which can be induced in amolecule,

u -Fl p MR I, (filasstone: loc. cit. P. 537] The HFP/C H, adduct isabout more polarizable than the TFE/C H adduct and therefore a bettersolvent for polar, or ionic, solutes. In addition, the HFPIC H adduct isthus a better solvent for organic reactions involving electrondisplacements. Conversely, the HFP/C H adduct is a poorer solvent forpurely covalent molecules than the TFE/C'M, adduct, a property that canbe used to advantage in working fluid applications.

In addition, the unexpectedly high dielectric constant 17-19) of the newdimer also gives it utility as an inert, non-functional solvent forfluoropolymer molecular weight determinations and fluorochemicalreactions. The dielectric constant is of the same order as pyridine(12.3) and acetone (20.7), two commonly used reaction and cleaningsolvents. A much lower value of the dielectric constant would bepredicted, however, because a range of about 1 to 7 (vapor and liquiddata) is obtained for such compounds as CClF CFgclz, CHCI F. CHClFCH;,CF;, (a Compound having the same ratio of H/F as the new compounds),CH -,CCIF CF CH- Cl, and CCl FCClF Solvents effects are demonstrated bythe fact that acetone and ethanol are only slightly soluble inhexafluoropropene dimer, but are completely soluble in the new mixeddimer.

Further insight into the solvent properties is gained by a considerationof the dipole moment of the cyclic HFP/C;,H,,- adduct which may beestimated from the measured dielectric constant. The total polarizationof any molecule at any instant in time is due to two factors: l thetotal polarization which can be induced in the molecule by an electricalfield (P,,) and (2) the polarization which is inherent in the moleculebecause of its structure P,,). The relation between the totalpolarization at any instant and the dielectric constant is gi\en b therelation The value for P,, may be obtained from P,,= P,;+ P l.] P l.lMR,3l.02,

and from the relation where N Avogadros number, 6.2 X l0 molecules/mole,

k R/N Boltzmanns constant,

R 8.3 l4 l0 ergs/mole/deg,

T absolute temperature, and

p.= dipole moment of the molecule,

It can be estimated that the dipole moment, a, is 2. [3 X 10 e.s. unitcm. or 2.]3D. This relatively large dipole moment (acetone is 2.7,butylamine is L4, and water is 1.84) implies a polar molecule and isevidence that the HFP/C H adduct has unusual solvent properties.

The linear adducts herein, CH CHCH- CF CFHCF and CH CH=CHCF CFHCF areuseful as comonomers in the preparation of ethylene and propylenepolymers in amounts of up to about 20% by weight of the ethylene orpropylene copolymer which is prepared by conven tional polymerizationtechniques well known for the production of olefin polymers. Thefluorinated comonomer gives the ethylene or propylene polymer bettermechanical processing characteristics (improved extrudability andmoldability), flame resistance, and increased resistance to solvents.The terminally unsaturated compound is the more preferred fluorinatedcomonomer because of its greater reactivity in the polymerization.

We claim:

1. A compound of the structure CH =CHCH CF CFHCF 2. A compound of thestructure 3. The method of preparing 4,4,5,6,6,6-hexafluorohexene-l and4,4,5,6,6,6-hexafluorohexene-2 which comprises reactinghexafluoropropylene and propylene in a mole ratio within the range ofabout lzl to [:20 at elevated temperatures of from about 200C to about800C and pressures ranging from one to about 500 atmospheres, andseparating said hexafluorohexenes from the l-trifluoromethyll ,2,2-trifluoro-4-methylcyclobutane coproduct also produced by said reaction.

4. The method of claim 3 wherein the reaction is carried out at atemperature within the range of 240C. to 350C.

5. The method according to claim 3 wherein the pressure is in the rangeof 50 to 200 atmospheres.

6. The method according to claim 4 wherein the pressure is in the rangeof 50 to 200 atmospheres.

7. The method of preparing 4,4,5,6.o,6-hexafluorohexene-l and4,4,5,6,6,6-hexafluorohexene-2 which comprises reactinghexafluoropropylene and propylene in a mole ratio within the range offrom about 1:1 to 1:20 wherein the reaction is catalyzed byditertiarybutyl peroxide and is carried out at temperatures on the orderof about C. and pressures ranging from one to about 500 atmospheres andseparating said hexafluorohexenes from the l-trifluoromethyLl,2,2-trifluoro-4-methylcyclobutane coproduct also produced by saidreaction.

embodied

1. A compound of the structure CH2 CHCH2CF2CFHCF3
 2. A compound of thestructure CH3CH CHCF2CFHCF3
 3. THE METHOD OF PREPARING4,4,5,6,6,6-HEXAFLUOROHEXENE-1 AND 4,4,5,6,6,6-HEXAFLUOROHEXENE-2 WHICHCOMPRISES REACTING HEXAFLUOROPROPYLENE AND PROPYLENE IN A MOLE RATIOWITHIN THE RANGE OF ABOUT 1:1 TO 1:20 AT ELEVATED TEMPERATUES OF FROMABOUT 200*C TO ABOUT 800*C AND PRESSURES RANGING FROM ONE TO ABOUT 500ATMOSPHERES, AND SEPARATTING SAID HEXAFLUOROHEXENES FROM THE1-TRIFLUOROMETHYL-1,2,2-TRIFLUORO-4-METHYLCYCLOBUTANE COPRODUCT ALSOPRODUCED BY SAID REACTION.
 4. The method of claim 3 wherein the reactionis carried out at a temperature within the range of 240*C. to 350*C. 5.The method according to claim 3 wherein the pressure is in the range of50 to 200 atmospheres.
 6. The method according to claim 4 wherein thepressure is in the range of 50 to 200 atmospheres.
 7. The method ofpreparing 4,4,5,6,6,6-hexafluorohexene-1 and 4,4,5,6,6,6-hexafluorohexene-2 which comprises reactinghexafluoropropylene and propylene in a mole ratio within the range offrom about 1:1 to 1:20 wherein the reaction is catalyzed byditertiary-butyl peroxide and is carried out at temperatures on theorder of about 120*C. and pressures ranging from one to about 500atmospheres and separating said hexafluorohexenes from the1-trifluoromethyl-1,2,2-trifluoro-4-methylcyclobutane coproduct alsoproduced by said reaction.